WASHINGTON (CN) – Expanding their investigation into President Donald Trump’s business dealings and potential violations of anti-corruption rules, House Democrats have demanded travel expenditure records from Vice President Mike Pence’s trip to Ireland this week that included a stay at a Trump resort.

According to a Thursday letter sent by the House Oversight Committee to the White House, Pence’s Chief of Staff Marc Short said Trump personally directed the vice president to stay at the Trump International Golf Links and Hotel in Doonbeg, saying, “You should stay at my place.”

The resort is nearly 200 miles from Dublin, the location of all of Pence’s official meetings this week.

According to the committee, Pence’s office later issued a statement denying that Trump told the vice president to stay at the property. The resort has reportedly been a problematic investment for the Trump Organization and has “failed to turn a profit in years,” according to the letter.

During a press conference Wednesday, Trump told reporters he “had no involvement” in Pence staying at the Doonbeg resort.

“It wasn’t my idea for Mike to go there. Mike went there because his family’s there, that’s my understanding of it,” Trump said. “I don’t suggest anything…I have a lot of hotels all over the place and people use them because they’re the best.”

In Thursday’s letter, Oversight Committee Chairman Elijah Cummings, D-Md., said the total cost of Pence’s trip to Ireland had not been made public but could be significant.

“President Trump stayed at his property in Doonbeg in June, which cost the American people an estimated $3.6 million,” Cummings wrote.

The letter also states, “The committee does not believe that U.S. taxpayer funds should be used to personally enrich President Trump, his family, and his companies.”

The Constitution’s so-called emoluments clauses prohibit the president from receiving gifts from foreign or state governments or officials while in office without congressional consent. Democrats say official state visits to Trump’s hotel properties could be a violation of those clauses.

The House Oversight Committee is requesting an itemized list of costs associated with Pence’s trip, along with a list for Trump’s June stay in Doonbeg.

Similarly, the House Judiciary Committee is investigating the president’s promotion of the Trump National Doral Miami resort, which he floated as a possible venue to host the next G7 summit.

The committee sent its own letter to the White House on Thursday asking for more information on the “apparent promotion and solicitation of foreign and U.S. government business.”

Chairman Jerry Nadler, D-.N.Y., said while White House officials have claimed it’s easier for the Secret Service and law enforcement to secure Trump’s resorts when he travels, there hasn’t been confirmation of that to support spending taxpayer dollars to do so.

“The threat that the President’s personal financial interests could shape decisions concerning official U.S. government activities is precisely the type of risk that the Emoluments Clauses were intended to minimize,” Nadler wrote. “The Doral and Doonbeg cases are just two of the many examples of the solicitation or receipt of foreign government spending to the benefit of the President’s private financial interests.”

Trump promoted the location as the next G7 venue during a press conference with German Chancellor Angela Merkel at last month’s summit in Biarritz, France.

“It’s a great place. It’s got tremendous acreage, many hundreds of acres so we can handle whatever happens. People really like it,” Trump said during the Aug. 26 press conference.

Trump took to Twitter the following day, addressing rumors of the Trump National Doral Miami resort being infested with bedbugs.

“The Radical Left Democrats, upon hearing that the perfectly located (for the next G-7) Doral National MIAMI was under consideration for the next G-7, spread that false and nasty rumor. Not nice!” Trump tweeted.